The inventor herein has recognized a need for an improved self-diagnosing battery cell monitoring system that can detect fault conditions in a battery cell voltage monitoring IC. The self-diagnosing battery cell monitoring system utilizes diagnostic flags associated with a digital voltage substrate, an analog differential voltage substrate, an analog voltage substrate in the battery cell voltage monitoring IC with encoded fault values or encoded non-fault values having Hamming distances of four from one another to obtain freedom from interference in detecting fault conditions.